Recently, the use of renewable energies is being expanded from the viewpoint of securing energy security and reducing the burden on the global environment. Among the dispersed power sources making use of renewable energies, solar photovoltaic generation (may hereinafter be referred to as “PV”) and wind-power generation are known.
The typical renewable energies mentioned above are dispersed power sources, and they are generally unstable in output compared with conventional thermal power generation or hydraulic power generation. Therefore, in cases where dispersed power sources are connected to a power system, a technical measure for dealing with sharp output variations is required.
In Patent Literature 1, a configuration in which the output variations of dispersed power sources are suppressed using NAS (sodium-sulfur) batteries and capacitors is partly disclosed (Patent Literature 1).
In Patent Literature 2, a configuration is disclosed in which a secondary battery for peak power smoothing is connected with a capacitor in parallel for complementing between charging and discharging of the secondary battery (Patent Literature 2).